In the metallurgical field it is necessary to obtain samples of the metal while it is in the molten state for various analyses to determine the composition and quality of the metal being processed. It is essential that the sample be a good representation of the metal in the furnace and that the sample be a good solid specimen free of extraneous material of any kind. It also is desirable to obtain a sample in a round flat form especially adapted for polishing and in the form of a pin that can be readily processed in the laboratory for metallurgical analyses.
It has been the conventional practice in the past to utilize a metal receptacle for receiving the molten metal to form the specimens for laboratory analyses. The receptacle with the specimen is broken open and disposed of. However, the use of a metal receptacle usually resulted in excessively rapid chilling and solidification of the specimen which will result in undesirable voids in the sample because the metal is not allowed to circulate sufficiently in the mold to vent all of the gases.
Moreover, the solidified metal sample adheres to the metal receptacle and it is difficult to break open the receptacle for gaining access to the sample.
When taking such sample of metal from a furnace it is imperative that the rate of cooling of the sample be controlled to prevent its rapid chilling and premature solidification. Such excessively rapid cooling produces a poor sample that is not entirely satisfactory for laboratory purposes. Thus, for example, it may cause stratification in the sample making it unsuitable for metallurgical analyses. Furthermore, such rapid cooling may trap gases in the metal which will produce undesirable voids in the sample.